1. Field of the Invention
This invention relates to a spindle apparatus and, more particularly, to a spindle apparatus operative by a fluid powered turbine (reaction) and having a handle portion and a head portion which are coupled to each other without using gears.
2. Description of the Prior Art
In the prior art, spindle devices may be utilized for performing a variety of functions, such as grinding, polishing, metal or plastic finishing, engraving, jewelry fabrication, drilling, deburring and so forth. These spindle devices normally include a handle portion having a primary rotatable shaft and a head or front end portion having a secondary rotatable shaft. The head portion of such devices may be arranged at a predetermined angle with respect to the handle portion. Accordingly, in these spindle devices, the axes of rotation of the primary and secondary axes are typically not parallel to each other. Such angled positioning of the head portion enables an operator to more easily reach a desired object.
Such prior art spindle devices normally utilize a so-called vane-type fluid motor which may be located in the handle portion and which is coupled to the primary shaft therein. The primary shaft, in turn, is coupled to the secondary shaft by way of a gear train having a plurality of gears.
The vane-type motor may be considered as a type of impulse turbine. Basically, in the vane-type motor, a fluid is directed in a stream or streams towards an outer periphery of a rotatable impeller or vane. The vane is coupled to a rotatable shaft which, in turn, is coupled to a rotatable tool, such as a grinder, a drill and so forth. The rotational speed of the vane, and the tool, is a function of fluid flow and the pressure of such fluid. Accordingly, the vane-type motor act as a "free speed motor".
In operation, a fluid, such as air, is supplied to the handle portion from an air supply, whereupon the fluid is directed to an input of the vane-type motor and from there to the outer periphery of the vane. As a result, the vane rotates causing the primary shaft to rotate which causes the gears to rotate which, in turn, causes the secondary shaft to rotate, thereby causing the grinding or finishing tool or such similar tool to rotate.
The vane-type fluid motors are relatively heavy and noisy. In addition, rotation of the gears produces relatively high vibration levels. Such undesirable characteristics may result in the operator becoming fatigued after using such device for only a relatively short period of time. As is to be appreciated, this may result in less productivity and/or poor workmanship.
Further, the gears normally require lubrication so as to operate properly and to increase the operating life of the gears. However, providing such lubrication is time consuming and increases the overall operating costs. Moreover, even with such periodic lubrication, the gears still wear and accordingly require maintenance and/or replacement.
Furthermore, vane-type motors are normally unable to maintain a constant rotational speed when operating under a load. That is, the vane-type motors can not be governed to a specific speed. Additionally, as previously described, vane-type motors are "free speed" motors and are sensitive to variations in flow and pressure. Accordingly, it may be difficult to maintain a tool coupled to a vane-type motor at a constant speed especially when subjected to varying loads. As is to be appreciated, the inability to maintain a constant rotational speed of a tool may adversely affect a desired operation. For example, an undesired sudden increase in the rotational speed of a grinding or drilling tool may result in more material being removed than desired.
Other conventional spindle devices, such as that described in U.S. Pat. No. 3,120,705, are utilized for dental purposes. In these spindle devices, an impulse turbine is located in the head portion of the spindle. As a result, the head portion in these devices is coupled to the handle portion without the use of gears or the like. The handle portion in these devices, unlike that in the previously described devices, does not include a primary shaft and instead includes additional channeling or tubing for directing the flow of received fluids therethrough. In addition to the impulse turbine, the head portion includes channeling or tubing and a shaft coupled to the motor. In operation, a fluid, such as air, is supplied through the channeling in the handle portion to an inlet of the channeling in the head portion and therefrom to an input of the impulse turbine, whereupon the fluid is directed through a nozzle to the outer periphery of the turbine rotor. As a result, the vane rotates causing the shaft to rotate which, in turn, causes a grinding-type tool to rotate.
An impulse turbine can be relatively heavy. By placing the relatively heavy impulse turbine in the head portion, the balance of the spindle device may be adversely affected, thereby making the use of such device difficult or cumbersome. Thus, the spindle devices having as impulse turbine located in the head portion may still be difficult to operate and when combined with the relatively high noise level produced by such motor as previously described, may cause operator fatigue.
Further, by using an impulse turbine, the spindle of the type in which the turbine is located in the head portion thereof, like the spindle having the motor located in the handle portion, is unable to maintain a constant rotational speed of the tool when subjected to varying loads.
Thus, the prior art has failed to provide a spindle which is relatively light weight, produces only a relatively low noise level and vibration level when operating, and maintains a constant rotational speed when subjected to a load.